A pallet changer includes: a machining-side linear guide rail 25 provided on a machining table 8 and extending in a Y-axis direction perpendicular to an X-axis direction (predetermined direction); preparation-side linear guide rails 26, 27 provided on workpiece preparation parts 9, 10 respectively, extending in the Y-axis direction, and coaxial with the machining-side linear guide rail 25; and linear guides 28 provided on respective pallets P1, P2 and slidably engageable with the machining-side and preparation-side linear guide rails 25 to 27, wherein, in changing the machining-side pallet P1 on the machining table 8 and the standby-side pallet P2 on the workpiece preparation part 10, the machining-side pallet P1 and the standby-side pallet P2 are moved in the Y-axis direction.